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US 12,183,795 B2Granted
Notch shape of trench gate bottom corner for better breakdown voltage of power MOSFET and IGBT with good trade off to ron and ox reliability
AssigneeSiEn (QingDao) Integrated Circuits Co., Ltd.
InventorsConghui Liu, Peng Li, Min-Hwa Chi
Life of this patent
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Abstract
The present invention provides a device having a trench gate structure and a method of making the same. The device comprises a substrate, a drift region, a well region, a trench gate, a heavily-doped region, and an electrode positioned on the heavily-doped region. The structure of the device is simple to provide good VDMOS and IGBT breakdown voltages, and meanwhile take on-state resistance and reliability of oxide into account.
Claims10
A device having a trench gate structure, comprising:
- a substrate having a first conductivity type, and the substrate having a first main surface and a second main surface opposite to the first main surface;
- a drift region formed on the first main surface of the substrate, the drift region having the first conductivity type, and a carrier content of the drift region being lower than that of the substrate;
- a well region formed on the drift region, and the well region having a second conductivity type opposite to the first conductivity type;
- a trench gate, the trench gate passing through the well region and reaching the drift region, a bottom corner of two sides of the trench gate having a recess expanding outwardly, and an internal angle of the recess being less than 90°;
- a heavily-doped region formed in the well region and at a side edge of the trench gate, and the heavily-doped region having the first conductivity type;
- and
- an electrode positioned on the heavily-doped region, and the electrode contacting with the heavily-doped region and at least partially extending in the well region.
4 more elements
A method of making a device having a trench gate structure, comprising steps of:
- providing a substrate, the substrate having a first conductivity type, and the substrate having a first main surface and a second main surface opposite to the first main surface;
- forming a drift region on the first main surface of the substrate, the drift region having the first conductivity type, and a carrier content of the drift region being lower than that of the substrate;
- forming a well region on the drift region, and the well region having a second conductivity type opposite to the first conductivity type;
- forming a trench gate passing through the well region and reaching the drift region, a bottom corner of two sides of the trench gate having a recess expanding outwardly, and an internal angle of the recess being less than 90°;
- forming a heavily-doped region in the well region and at a side edge of the trench gate, and the heavily-doped region having the first conductivity type;
- and
- positioning an electrode on the heavily-doped region, and the electrode contacting with the heavily-doped region and at least partially extending in the well region.
4 more elements
Dependencies are inferred from the claim text.